[LPC11U68] Fix GPIO init for specific pins

* Add GPIO initialization value for P0_12, P0_13 and P0_14 since default
mode for them are other than GPIO
* This issue reported here:
https://developer.mbed.org/questions/4874/Using-SPI-on-LPCXpresso11U68/
[HAL][KSDK] Fixed ACK/NACK received inverted (https://github.com/mbedmicro/mbed/issues/661)

As reported by Geremia G
(http://developer.mbed.org/forum/bugs-suggestions/topic/5220/)
Merge pull request #684 from Sissors/ksdk

Targets: KSDK - Fix ACK/NACK received inverted (issue #661)
Merge pull request #686 from GustavWi/iar_mbed

Toolchain: IAR - lpc1347 startup fix
Merge pull request #679 from toyowata/master

Targets: LPC11U68 - Fix GPIO init for specific pins